This study aimed to determine the seroprevalence of Kaposi’s sarcoma-associated herpesvirus(KSHV) and related factors in men who have sex with men (MSM) in China. A total of 208 subjects were recruited from eastern China from 2008 to 2009. Plasma samples were collected and screened for KSHV, HIV and syphilis. Overall, KSHV seroprevalence was 32.7% in the subjects. About 92.7% of subjects reported having ever had anal sex with a man, of whom 67.8% had receptive anal sex and 77.9% had insertive anal sex. About 93.1% of the study participants reported having had oral sex with a man, of whom 76.0% had receptive oral sex and 56.7% had insertive oral sex. KSHV seropositivity was independently associated with receptive anal sex[odds ratio (OR) 2.68, 95% confidence interval (CI) 1.15–6.23], syphilis (OR 3.25, 95% CI1.56–6.76) and HSV-2 infection (OR 2.40, 95% CI 1.09–5.26). KSHV infection is highly prevalent and is probably sexually transmitted among MSM in eastern China.